In a diesel engine, turbo surge occurs when intake air is not moving fast enough to overcome surface friction in a turbo compressor. During turbo surge, air flows backward and swirls with intake air, which results in noise and vibrations.
A swirl control valve system is applied to most common diesel vehicles. The swirl control valve system includes a high swirl section at medium or low speeds at which the system closes valves for four of the eight ports in the intake system. The swirl control valve system also includes a flow-increasing section at high speeds at which the system fully opens all of the eight ports in the intake system.
However, common swirl control valve systems do not include logic for reducing surge noise created during Tip Out, i.e. the accelerator pedal is suddenly released from a depressed position to a nearly or completely released position.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.